A Lebanese army soldier, stands on top of a tank during clashes that erupted between pro and anti-Syrian regime gunmen in the northern port city of Tripoli, Lebanon, Wednesday December 5, 2012. Gunmen loyal to opposite sides in neighboring Syria's civil war battled in the streets of northern Lebanon and the death toll from two days of fighting was at least five killed and tens wounded, officials said. The fighting comes at a time of deep uncertainty in Syria, with rebels closing in on President Bashar Assad's seat of power in Damascus.

For months, world leaders and the media have underestimated the strength of the insurgency in Syria. Now, with Bashar al Assad’s regime disintegrating, the international community must come to terms with the impending rebel victory.

It is hard to pigeonhole courses of action into "left" or "right" on this issue, and there are no risk-free options, but the United States needs to play a more decisive role in shaping the future of the region—and quickly. The irony is that while the U.S. was worried about avoiding another “Iraq quagmire,” Syria has degraded from a peaceful revolution into an armed rebellion, and now resembles a free-for-all power grab by regional powers and extremists.

Just today, the rebels captured a major government building in Al Safirah—home to what may be Assad's largest chemical weapons facility—and according to reports they are closing in on the base containing the weapons depot. If this base were to fall, there's no telling where these weapons will wind up.

The United States and its NATO allies have to ensure that Assad falls on their terms to ensure a new, peaceful democratic government that respects minorities and safeguards Assad's chemical weapons stockpile—weapons which, if no action is taken, could fall into the wrong hands. While the Syrian people have demonstrated a commitment to tolerance and democracy in large protest rallies held every Friday where they express their desires, there are radical wings in the insurgency committed to establishing a radical Islamic state, many who come from Iraq and are affiliated with Al Qaeda. It is in the best interests of the region, and the entire world, that the most moderate voices prevail once Assad is no longer in control.

The fear is that the regime may fall before the international community has established a transitional government it can influence. The National Coalition, the fledgling opposition leadership group, is working to establish control of both the civilian leadership that now runs large parts of the country, and the military wing of the insurgency. So far, however, it is too young, and too detached from what's happening on the ground in Syria to have any influence. If the regime falls before the National Coalition establishes control, there is no telling who will fill the vacuum, but the U.S., NATO, and Turkey may have very little power to affect a peaceful and orderly transition.

The United States has the option of intervening in Syria to ensure that the rebels who share its values are the strongest once Assad is gone. But selectively arming some rebel groups may not be enough; rebels have already captured very powerful weapons from the regime. Without equipping rebels with a significant number of anti-aircraft weapons—a course of action the international community has been hesitant to pursue—no amount of arms will achieve the desired results. A partial no-fly zone over rebel-held territory in northern Syria—another course of action the international community is considering—would provide the rebels the ability to capture the remaining pockets of Assad resistance and focus on launching fresh offensives. The move is risky, as it could provoke a wider military response against Turkey, a key NATO power that would be essential to any military intervention in Syria. A more robust approach is for the United States and NATO to establish a no-fly zone that stretches over Damascus, allowing the rebels to directly attack the heart of the regime. To be clear, this option would require an all-out air war against Assad. Just as we saw in Libya, in order to ensure the safety of the aircraft involved in such an action, and the countries from where this mission would be launched (Turkey, and possibly Jordan), Assad's air defenses would need to be removed, his air bases made inoperative, and his long-range weapons, particularly his artillery and ballistic missile sites, would need to be destroyed. The Syrian military is much stronger than Libya's was, and so the scale of such an operation would perhaps be similar to the First Gulf War. This option gives the NATO nations the most control over what happens next, would bring the fastest end to the conflict, but it also carries the most risks. Assad could respond by launching his chemical weapons, the only real power the regime has left.

Despite the urgency, NATO, the United States, and Turkey are still unsure as to whether they should militarily intervene in Syria. The Patriot missiles that will be deployed to Turkey in the next few weeks will give them some options. By themselves, these missiles would not be capable of establishing an effective no-fly zone over the border. However, they are designed to counter a future threat. Once in place, they would allow the United States, Turkey, or NATO to ratchet up pressure on Assad with the knowledge that they could intervene if needed. Turkey would be more protected from Assad's only real threat—ballistic missiles armed with chemical warheads—a threat Assad is unlikely to use unless he is facing full-scale invasion by outside forces as it would likely trigger a military response. In short, this is the boldest move made by NATO so far, but it is only a preparation for future actions that may or may not be taken.

There is a remote chance that a peaceful end to this crisis could be found, but it would require Russia, an ardent supporter of Bashar al Assad, to play a more pivotal role in ending this conflict. The Russian government is now realizing that they need to lean on Assad and pressure him to accept a diplomatically negotiated settlement that would allow Assad to exit Syria in a peaceful transition of power. From Russia's point of view, the regime could fall, or worse, the world could intervene, spelling a complete diplomatic and geopolitical loss for Russia, a country which has already lost a key ally and trading partner in the region, Colonel Qaddafi. The problem is that it remains unclear if Assad would accept an offer to leave, and it is also unclear if the rebels would stop their advance. After all, they are winning, they know they are winning, and they do not trust the rest of the regime any more than they trust Assad, so the insurgents have little incentive to stop.

There is an option which the Obama administration has not yet used—it could bluff, and at least threaten to take military action. The message from the U.S. administration has been clear—it wants to avoid a military intervention in Syria, and would only do so if Assad used (or lost control of) his chemical weapons. This has been a signal to the Assad regime, and its allies Russia and China, that the United States would stay out of this fight. Instead, the United States, through the U.N., has pursued a diplomatic solution. The likelihood that the West can find a political solution to this crisis is now, and has always been, almost zero. It is now time for the United States to begin to prepare for military action, adding pressure on Assad to accept a political transition negotiated by Russia. If Assad, and Russia, knew that international military intervention was on the table, it may be just enough to inspire them to act.